In 1759, at the height of the Seven Years’ War, when Great Britain was suffering a series of military reversals, Montagu considered his country’s plight in an historical context formed by the study of five ancient republics: Sparta, Athens, Thebes, Carthage, and Rome. Montagu’s focus on the ancient republics gives his contribution a distinctive twist to the chorus of voices lamenting Britain’s decline, and his analysis exerted influence in three momentous eighteenth-century crises: the Seven Years’ War, the American War of Independence, and the French Revolution. This is the first modern edition of Montagu’s work.